function send_login_info(){
    var id = document.getElementById("id").value;
    var psw = document.getElementById("psw").value;
    console.log(id);
    console.log(psw);
    $.ajax({
        url: "/check",
        type: "POST",
        dateType: "json",
        data: {
            "id": id,
            "psw": psw
        },
        success: function(arg){
            if(arg == 'correct'){
                window.location = '/upload';
            }else{
                console.log('wrong');
                alert('Wrong password');
            }
        },
        fail: function(arg){
            console.log('fail');
        }
    });
}